The present invention relates to light emitting flat-panel displays, and more particularly to means for signaling the remaining useful life of such displays.
Emissive flat-panel display devices are widely used in conjunction with computing devices and in particular with portable devices. Over time, the efficiency and effectiveness of the displays change and the quality of the displays, particularly for sensitive applications such as imaging, declines. This decrease in quality can be due to changes in the materials comprising the display, degradation in electronic components, and the like.
In particular, organic light emitting diode (OLED) display devices suffer from changes in the organic light emitting materials within the display. The changes affect the efficiency and brightness of the display. These changes may also be color dependent, that is, the changes affect the different colors in the display device in different ways so that over time not only does the power efficiency of the display device decrease but the color balance changes. These changes result in an inferior display with poor image and color rendition.
Some imaging applications are critical, that is, they cannot be allowed to fail. For example, some applications within the military and medical fields fall into this critical category. Moreover, within large systems, regular maintenance is often used to replace components, such as display devices, at fixed intervals whether or not the device is about to fail. Unnecessary replacement wastes resources. To address these concerns, some imaging systems, such as white-light projectors, utilizing radiation sources measure the time that the radiation source is turned on. Comparing this measurement to known life times allows a system to recommend maintenance or replacement. However, this approach is not useful for displays with light emitting elements and variable display content since the degradation of the light emitting elements is dependent on the exercise of each element.
There is a need therefore for an improved emissive flat-panel display system that improves the maintainability and reduces the operational costs of the display system.
The need is met according to the present invention by providing a light emitting flat-panel display that includes a plurality of light emitting diodes; a sensor for sensing the light output of at least one of the light emitting diodes to produce a light output signal; and a display controller responsive to the light output signal for producing a signal representing the remaining useful life of the display. In a preferred embodiment, the display is an organic light emitting diode display.
The present invention has the advantage that it reduces the life-cycle costs and improves the reliability of an emissive flat-panel display device.